1. Field of the Invention
Embodiments of the invention relate to a touch sensor integrated type display device capable of recognizing a user's touch operation. More particularly, the present invention relates to a touch sensor integrated type display device capable of implementing an in-cell touch sensor through a simple pixel configuration and enhancing touch sensitivity.
2. Discussion of the Related Art
In recent years, various input devices such as a keyboard, a mouse, a joystick, and a digitizer have been used to allow users to interface with home appliances or information telecommunication devices. However, when the user makes use of these input devices, user's dissatisfaction increases because the user is required to learn how to use the input devices and the input devices occupy space. Therefore, a convenient and simple input device that can reduce erroneous operation is required. In response to this demand, a touch sensor for enabling the user to input information by directly touching the screen with his or her hand or a pen was suggested.
The touch sensor has a simple configuration capable of reducing erroneous operations. The user can also perform an input action without using a separate input device, and can quickly and easily manipulate a device through contents displayed on the screen. Accordingly, the touch sensor has been applied to various display devices.
The touch sensor used in the display devices may be classified into an add-on type touch sensor and an on-cell type touch sensor. The add-on type touch sensor is configured such that a display device and a touch sensor are individually manufactured and then the touch sensor is attached to an upper substrate of the display device. The on-cell type touch sensor is configured such that components constituting a touch sensor are directly formed on the surface of the upper glass substrate of the display device.
There is a problem that a thickness of the display device increases because the add-on type touch sensor has the structure in which the touch sensor is mounted on the display device. Further, the visibility of the display device is reduced because of a reduction in brightness of the display device due to the increased thickness.
On the other hand, the on-cell type touch sensor shares the glass substrate with the display device because the touch sensor has the structure in which the touch sensor is formed on the surface of the glass substrate of the display device. Therefore, a thickness of the display device using the on-cell type touch sensor is less than a thickness of the display device using the add-on type touch sensor. However, the entire thickness of the display device using the on-cell type touch sensor increases because of a touch driving electrode layer, a touch sensing electrode layer, and an insulating layer for insulating the touch driving electrode layer and the touch sensing electrode layer which constitute the on-cell type touch sensor.
Accordingly, a touch sensor integrated type display device capable of using touch driving electrodes and touch sensing electrodes of a touch sensor as a common electrode of the display device was devised, so as to solve the above-described problem.
However, because the related art touch sensor integrated type display device has to divide the common electrode of the display device to form the touch driving electrodes and the touch sensing electrodes on a single layer, various types of display pixels, separate wires for connecting the touch driving electrodes to the touch sensing electrodes, and contact holes are complicatedly formed in a unit pattern of the touch electrode. To implement the touch sensor in such a complicated structure of the display device, various kinds of display unit pixels have to be combined to form a touch unit pattern composed of several hundreds to several thousands of display unit pixels.
In this instance, complicated configuration of the display pixels results in a reduction in display characteristics, and it is difficult to perform a process for the complicated configuration of the touch sensor and the touch unit pattern and to conduct an image test.